1. Technical Field
The disclosure relates to a power transmission device for a vehicle and, in particular, relates to a technique of suppressing the wear of a rattling suppression member due to radial vibration.
2. Description of Related Art
For example, the following vehicle power transmission device is known. The vehicle power transmission device includes a rotor shaft and a gear shaft. The rotor shaft is formed with first spline teeth and is rotatably supported by a pair of first bearings. The gear shaft is formed with second spline teeth that are spline-fitted to the first spline teeth, and is supported by a pair of second bearings so as to be rotatable about an axis common to the rotor shaft. In this vehicle power transmission device, for example, when vibration such as torque fluctuation of an engine is transmitted when the rotor shaft is rotated with no load, there is a possibility that rattling, radial vibration, and noise such as tooth hitting noise may occur at a spline fitting portion. The spline fitting portion is coupled in a power transmittable manner to a driving source such as the engine via the gear shaft meshing with a gear to which the power from the driving source is transmitted.
In order to reduce the problem of radial vibration and tooth hitting noise at the spline fitting portion, for example, in Japanese Patent Application Publication No. 2004-353785 (JP 2004-353785 A), the clearance in the circumferential direction between female spline teeth and male spline teeth forming a spline fitting portion is set to be smaller than that between standard spline teeth. In this way, rattling at the spline fitting portion is suppressed.
Further, in order to suppress rattling at the spline fitting portion, for example, a rattling suppression member that is elastically deformable in the radial direction is disposed between a rotor shaft and a gear shaft facing the rotor shaft in the radial direction. By suppressing rattling at the spline fitting portion in this way, it is considered to reduce the occurrence of radial vibration and noise such as tooth hitting noise.